Dental equipment commonly found in a dentist's office today includes a hand held instrument, such as a high speed or low speed drill which is operated by a foot pedal rheostat. The equipment includes several tubes gathered in an adaptor to connect the instrument to a source of compressed air, a source of pressurized water, and an exhaust outlet. The instrument can be easily disconnected from the tubes for cleaning purposes by way of a threaded sleeve coupler. Generally the instrument is sterilized after every use and made ready for the next patient. The water and air, however, are not always filtered to remove dirt and other contamination, and the exhaust which may contain water, air, oil, etc. is frequently open to the atmosphere.
It is an object of this invention to provide a filter cartridge which is designed to fit snugly between the instrument handpiece and the adaptor so as to filter the lines of air, water, and exhaust going to and from the handpiece. It is another object of the invention to provide an easily replaceable filter cartridge to remove dirt, bacteria, and the like from the lines leading to the handpiece. Still other objects will become apparent from the more detailed description which follows.